1. Technical Field
The present disclosure relates to a carbon dioxide reducing method, a carbon dioxide reducing cell, and a carbon dioxide reducing apparatus.
2. Related Art
Japanese Patent Laid-Open Publication No. S55-105625 (Patent Literature 1), Japanese Patent No. 2526396 (Patent Literature 2), Japanese Patent No. 4158850 (Patent Literature 3), Japanese Patent No. 3876305 (Japanese Patent Laid-Open Publication No. 2003-275599) (Patent Literature 4), Japanese Patent Laid-Open Publication No. 2013-017929 (Patent Literature 5), Japanese Patent No. 2646834 (Japanese Patent Laid-Open Publication No. H04-166076) (Patent Literature 6), Japanese Patent Laid-Open Publication No. 2010-064066 (Patent Literature 7), Japanese Patent Laid-Open Publication No. 2011-094194 (Patent Literature 8), Japanese Patent Laid-Open Publication No. H05-311476 (Patent Literature 9), Japanese Patent Laid-Open Publication No. H07-188961 (Patent Literature 10), WO 2012/046374 (Patent Literature 11) and Japanese Patent Laid-Open Publication No. 2003-238104 (Patent Literature 12) disclose methods for reducing carbon dioxide, using optical energy.
Japanese Patent Laid-Open Publication No. S55-105625 (Patent Literature 1) and Japanese Patent No. 2526396 (Patent Literature 2) disclose methods of using, as a photocatalyst material, an oxide semiconductor such as titania to reduce carbon dioxide.
Japanese Patent No. 4158850 (Patent Literature 3) discloses a technique of using a photocatalyst material synthesized from a predetermined metal and semiconductor to reduce carbon dioxide.
Japanese Patent No. 3876305 (Japanese Patent Laid-Open Publication No. 2003-275599) (Patent Literature 4) and Japanese Patent Laid-Open Publication No. 2013-017929 (Patent Literature 5) disclose methods of irradiating a specific photocatalyst with sunlight or the like to reduce carbon dioxide.
Japanese Patent No. 2646834 (Japanese Patent Laid-Open Publication No. 04-166076) (Patent Literature 6) discloses a photosynthesis reactor system in which sunlight is concentrated to reduce carbon dioxide through photosynthesis organisms.
Japanese Patent Laid-Open Publication No. 2010-064066 (Patent Literature 7) and Japanese Patent Laid-Open Publication No. 2011-094194 (Patent Literature 8) disclose methods of irradiating a cathode formed of a photocatalyst composed of a semiconductor material and a metal complex material with light to reduce carbon dioxide.
Japanese Patent Laid-Open Publication No. 05-311476 (Patent Literature 9) and Japanese Patent Laid-Open Publication No. 07-188961 (Patent Literature 10) disclose methods of irradiating an anode composed of a semiconductor material such as titania with light to reduce carbon dioxide on a cathode. The methods disclosed in Japanese Patent Laid-Open Publication No. 05-311476 (Patent Literature 9) and Japanese Patent Laid-Open Publication No. 07-188961 (Patent Literature 10) require an external power source, such as a solar battery or potentiostat, separately.
WO 2012/046374 (Patent Literature 11) discloses a method of irradiating an anode made of gallium nitride with light to reduce carbon dioxide on a cathode. The method disclosed in WO 2012/046374 does not require an external power source such as a solar battery or potentiostat.
Japanese Patent Laid-Open Publication No. 2003-238104 (Patent Literature 12) discloses an optically-generating device for generating hydrogen from sunlight, the optically-generating device including an anode having] a photocatalyst layer formed on a surface of a p-type semiconductor layer of a solar cell having a pn junction.
However, conventional techniques do not make it possible to subject carbon dioxide to reducing treatment to produce a reduction product with a high efficiency.